1. Field of the Invention
The present invention relates to a microwave oven and, more particularly, to a microwave oven in which a turntable, for bearing food thereon, is installed on the bottom of a cooking compartment in a rotatable and reciprocally movable manner, thereby enabling uniform cooking of the food.
2. Description of the Related Art
In general, a microwave oven is an appliance in which food is cooked by frictional heat of water molecules, produced as high-frequency waves generated from a magnetron, are irradiated to the interior of a cooking compartment to repeatedly convert the molecular arrangement of water contained in the food.
Such a microwave oven comprises a body forming an outer appearance of the microwave oven, and a rectangular box-shaped inner case for dividing the interior of the body into a cooking compartment inside the inner case, and an electric element compartment outside the inner case.
On the bottom of the cooking compartment is installed a turntable so that the turntable is rotatable in a state wherein food is disposed thereon. Rotation of the turntable is achieved by a motor mounted at the outer lower surface of the inner case. Inside the electric element compartment are mounted a magnetron for generating high-frequency waves and irradiating the waves to the interior of the cooking compartment, a high-pressure condenser, and a high-pressure transformer for applying a high voltage to the magnetron, etc.
When the microwave oven configured as stated above is operated, the high-frequency waves generated from the magnetron are irradiated to the interior of the cooking compartment, thus allowing the food, rotating along with the turntable, to be cooked as the high-frequency waves are irradiated thereto.
Such a conventional microwave oven, however, has a limitation to uniformly cook the food since the turntable is rotated in a prescribed fixed position on the bottom of the cooking compartment.
In order to overcome the above problem, Korean Registration Patent No. 10-0423993 discloses a microwave oven comprising a turntable, which is rotatable and reciprocally movable, for enabling uniform cooking of food disposed on the turntable.
The disclosed microwave oven further comprises an elongated slot formed at the bottom of the cooking compartment, a shaft coupled at an upper end thereof to a lower surface of the turntable, a lower end of the shaft extending downwardly through the elongated slot below the cooking compartment, a pinion formed at an outer circumference of the shaft at the outside of the cooking compartment, a guide member formed with a rack to be engaged with the pinion, the guide member being fixedly positioned below the cooking compartment, a first link, having a first end hingedly connected to the lower end of the shaft, and a second moveable end, and a second link, having a first end hingedly connected to the second movable end of the first link, and a second end fixed to a rotating shaft of a motor mounted below the cooking compartment.
With such a configuration, if the second link is rotated in one direction along with the rotating shaft of the motor, the first link is pulled toward or pushed away from the motor as the pinion is rotated forward or reverse along the rack according to a rotation range of the second link, thereby causing the shaft to rotate and linearly reciprocate along the elongated slot. This makes it possible for the turntable to rotate as well as linearly reciprocate on the bottom of the cooking compartment along with the shaft, thus enabling uniform cooking of the food on the turntable.
In the above described conventional microwave oven, between the bottom of the cooking compartment and the turntable is installed a sliding member. The sliding member serves to reduce a frictional resistance between the turntable and the bottom of the cooking compartment, thereby securing smooth rotation and linear reciprocation of the turntable. For this, the sliding member is made of a material having a low frictional coefficient.
A problem of the conventional microwave oven is that the turntable is rotated and linearly reciprocated in a surface-to-surface contact state with the sliding member, resulting in interference between rotation and linear reciprocation of the turntable, and limiting smooth operation of the turntable. In a surface-to-surface contact state between the turntable and the bottom of the cooking compartment, furthermore, if a relatively large load is applied to the bottom of the cooking compartment due to heavy foodstuff disposed on the turntable, a frictional force between the turntable and the bottom of the cooking compartment is increased largely, thereby hindering smooth rotation and linear reciprocation of the turntable.